Lin-Manuel Miranda's New Film 'Octet' Just Cast Amanda Seyfried and Rachel Zegler — Here Is Why This Is the Most Anticipated Movie Musical in Years

Lin-Manuel Miranda has revealed the cast for Octet, his new film musical, which will star Amanda Seyfried and Rachel Zegler. Here is what the project is, what Miranda has said about it, and why it represents a significant moment for original film musicals.

Lin-Manuel Miranda revealed the primary casting of his upcoming film musical Octet on or around April 14, 2026, with Amanda Seyfried and Rachel Zegler confirmed as leads. The announcement, noted in Just Jared's entertainment coverage, positions Octet as one of the most anticipated original film musicals in the pipeline — both because of Miranda's specific track record (Hamilton, In the Heights, the Tick Tick Boom adaptation) and because the specific combination of Seyfried and Zegler creates two leading performances from actors whose musical and dramatic ranges are among the strongest of their respective generations.

Octet is an original stage musical by Dave Malloy — the composer and lyricist behind Natasha, Pierre & The Great Comet of 1812, one of Broadway's most original and theatrically adventurous works of the 2010s. Miranda's adaptation brings Malloy's work to the screen through the specific transformation process that Hamilton demonstrated was possible: taking theatrical musical language and finding the cinematic vocabulary that preserves its essential qualities while giving it the specific visual and sonic properties that make film musicals resonate differently than their stage originals.

Amanda Seyfried's musical credentials are extensive and often undersold: her work in Mamma Mia! demonstrated genuine musical theatre instincts that the specific format of a jukebox movie musical partially obscured; her subsequent career in drama (Mank, The Dropout, her Emmy-winning work in The Dropout) has established her as one of her generation's most technically accomplished screen performers.

Rachel Zegler arrives at Octet in the specific position of an artist whose trajectory has been defined by exactly the kind of original musical work that Miranda is attempting. Her West Side Story debut, her work in The Hunger Games: The Ballad of Songbirds & Snakes, and her recent Olivier Award win for the London production of Snow White have each added specific layers to a performance identity that makes her ideally positioned for material as demanding as Malloy's compositional and lyrical style requires.

The film musical landscape in 2026 is defined partly by the specific commercial uncertainty that follows several underperforming high-budget musical adaptations and partly by the genuine creative ambition that a small number of projects — Wicked, the planned Mamma Mia sequel, Octet — represent. Miranda's specific track record of translating theatrical ambition into commercially viable cinema makes Octet different from many projects in this category: his ability to simultaneously honour theatrical roots and create genuinely cinematic work is among the most valuable skills in the contemporary musical adaptation ecosystem.